1,292 research outputs found
Deep Learning-Aided Subspace-Based DOA Recovery for Sparse Arrays
Sparse arrays enable resolving more direction of arrivals (DoAs) than antenna
elements using non-uniform arrays. This is typically achieved by reconstructing
the covariance of a virtual large uniform linear array (ULA), which is then
processed by subspace DoA estimators. However, these method assume that the
signals are non-coherent and the array is calibrated; the latter often
challenging to achieve in sparse arrays, where one cannot access the virtual
array elements. In this work, we propose Sparse-SubspaceNet, which leverages
deep learning to enable subspace-based DoA recovery from sparse miscallibrated
arrays with coherent sources. Sparse- SubspaceNet utilizes a dedicated deep
network to learn from data how to compute a surrogate virtual array covariance
that is divisible into distinguishable subspaces. By doing so, we learn to cope
with coherent sources and miscalibrated sparse arrays, while preserving the
interpretability and the suitability of model-based subspace DoA estimators.Comment: 4 pages, 4 figure
Implementation and Evaluation of Power Consumption of an Iris Pre-processing Algorithm on Modern FPGA
In this article, the efficiency and applicability of several power reduction techniques applied on a modern 65nm FPGA is described. For image erosion and dilation algorithms, two major solutions were tested and compared with respect to power and energy consumption. Firstly the algorithm was run on a general purpose processor (gpp) NIOS and then hardware architecture of an Intellectual Property (IP) was designed. Furthermore IPs design was improved by applying a number of power optimization techniques. They involved RTL level clock gating, power driven synthesis with fitting and appropriate coding style. Results show that hardware implementation is much more energy efficient than a general purpose processor and power optimization schemes can reduce the overall power consumption on an FPGA
CN and HCN in Dense Interstellar Clouds
We present a theoretical investigation of CN and HCN molecule formation in
dense interstellar clouds. We study the gas-phase CN and HCN production
efficiencies from the outer photon-dominated regions (PDRs) into the opaque
cosmic-ray dominated cores. We calculate the equilibrium densities of CN and
HCN, and of the associated species C+, C, and CO, as functions of the
far-ultraviolet (FUV) optical depth. We consider isothermal gas at 50 K, with
hydrogen particle densities from 10^2 to 10^6 cm^-3. We study clouds that are
exposed to FUV fields with intensities 20 to 2*10^5 times the mean interstellar
FUV intensity. We assume cosmic-ray H2 ionization rates ranging from 5*10^-17
s^-1, to an enhanced value of 5*10^-16 s^-1. We also examine the sensitivity of
the density profiles to the gas-phase sulfur abundance.Comment: Accepted for publication in ApJ, 33 pages, 8 figure
Psychosocial aspects of closed- and open-loop insulin delivery: closing the loop in adults with Type 1 diabetes in the home setting.
AIMS: To explore the psychosocial experiences of closed-loop technology and to compare ratings of closed- and open-loop technology for adults with Type 1 diabetes taking part in a randomized crossover study. METHODS: Adults (aged > 18 years) on insulin pump therapy were recruited to receive a first phase of either real-time continuous glucose monitoring with overnight closed-loop or real-time continuous glucose monitoring alone (open-loop) followed by a second phase of the alternative treatment in random order, at home for 4 weeks, unsupervised. Participants were invited to share their views in semi-structured interviews. The impact of the closed-loop technology, positive and negative aspects of living with the device overnight, along with the hopes and anxieties of the participants, were explored. RESULTS: The participants in the trial were 24 adults with a mean (sd) age of 43 (12) years, of whom 54% were men. The mean (range) interview duration was 26 (12-46) min. Content and thematic analysis showed the following key positive themes: improved blood glucose control (n = 16); reassurance/reduced worry (n = 16); improved overnight control leading to improved daily functioning and diabetes control (n = 16); and improved sleep (n = 8). The key negative themes were: technical difficulties (n = 24); intrusiveness of alarms (n = 13); and size of equipment (n = 7). Of the 24 participant, 20 would recommend the closed-loop technology. CONCLUSIONS: Closed-loop therapy has positive effects when it works in freeing participants from the demands of self-management. The downside was technical difficulties, particularly concerning the pump and 'connectivity', which it is hoped will improve. Future research should continue to explore the acceptability of the closed-loop system as a realistic therapy option, taking account of user concerns as new systems are designed. Failure to do this may reduce the eventual utility of new systems.Diabetes UKThis is the accepted manuscript. The final version is available at http://dx.doi.org/10.1111/dme.12706
Self-Consistent Field study of Polyelectrolyte Brushes
We formulate a self-consistent field theory for polyelectrolyte brushes in
the presence of counterions. We numerically solve the self-consistent field
equations and study the monomer density profile, the distribution of
counterions, and the total charge distribution. We study the scaling relations
for the brush height and compare them to the prediction of other theories. We
find a weak dependence of the brush height on the grafting density.We fit the
counterion distribution outside the brush by the Gouy-Chapman solution for a
virtual charged wall. We calculate the amount of counterions outside the brush
and find that it saturates as the charge of the polyelectrolytes increases
Detecting K-complexes for sleep stage identification using nonsmooth optimisation
The process of sleep stage identification is a labour-intensive task that involves the specialized interpretation of the polysomnographic signals captured from a patient’s overnight sleep session. Automating this task has proven to be challenging for data mining algorithms because of noise, complexity and the extreme size of data. In this paper we apply nonsmooth optimization to extract key features that lead to better accuracy. We develop a specific procedure for identifying K-complexes, a special type of brain wave crucial for distinguishing sleep stages. The procedure contains two steps. We first extract “easily classified” K-complexes, and then apply nonsmooth optimization methods to extract features from the remaining data and refine the results from the first step. Numerical experiments show that this procedure is efficient for detecting K-complexes. It is also found that most classification methods perform significantly better on the extracted features
Infrared spectroscopy of NGC 1068: Probing the obscured ionizing AGN continuum
The ISO-SWS 2.5-45 um infrared spectroscopic observations of the nucleus of
the Seyfert 2 galaxy NGC 1068 (see companion paper) are combined with a
compilation of UV to IR narrow emission line data to determine the spectral
energy distribution (SED) of the obscured extreme-UV continuum that
photoionizes the narrow line emitting gas in the active galactic nucleus. We
search a large grid of gas cloud models and SEDs for the combination that best
reproduces the observed line fluxes and NLR geometry. Our best fit model
reproduces the observed line fluxes to better than a factor of 2 on average and
is in general agreement with the observed NLR geometry. It has two gas
components that are consistent with a clumpy distribution of dense outflowing
gas in the center and a more extended distribution of less dense and more
clumpy gas farther out that has no net outflow. The best fit SED has a deep
trough at ~4 Ryd, which is consistent with an intrinsic Big Blue Bump that is
partially absorbed by ~6x10^19 cm^-2 of neutral hydrogen interior to the NLR.Comment: 15 pp, 4 figures, ApJ accepte
Short-lived star-forming giant clumps in cosmological simulations of z~2 disks
Many observed massive star-forming z\approx2 galaxies are large disks that
exhibit irregular morphologies, with \sim1kpc, \sim10^(8-10)Msun clumps. We
present the largest sample to date of high-resolution cosmological SPH
simulations that zoom-in on the formation of individual M*\sim10^(10.5)Msun
galaxies in \sim10^(12)Msun halos at z\approx2. Our code includes strong
stellar feedback parameterized as momentum-driven galactic winds. This model
reproduces many characteristic features of this observed class of galaxies,
such as their clumpy morphologies, smooth and monotonic velocity gradients,
high gas fractions (f_g\sim50%) and high specific star-formation rates
(\gtrsim1Gyr^(-1)). In accord with recent models, giant clumps
(Mclump\sim(5x10^8-10^9)Msun) form in-situ via gravitational instabilities.
However, the galactic winds are critical for their subsequent evolution. The
giant clumps we obtain are short-lived and are disrupted by wind-driven mass
loss. They do not virialise or migrate to the galaxy centers as suggested in
recent work neglecting strong winds. By phenomenologically implementing the
winds that are observed from high-redshift galaxies and in particular from
individual clumps, our simulations reproduce well new observational constraints
on clump kinematics and clump ages. In particular, the observation that older
clumps appear closer to their galaxy centers is reproduced in our simulations,
as a result of inside-out formation of the disks rather than inward clump
migration.Comment: 11 pages, 6 figures, 1 table. Accepted for publication in the
Astrophysical Journa
Indonesians Human Leukocyte Antigen (HLA) Distributions and Correlations with Global Diseases
In Human, Major Histocompatibility Complex known as Human
Leukocyte Antigen (HLA). The HLA grouped into three subclasses
regions: the class I region, the class II region, and the class III region.
There are thousands of polymorphic HLAs, many of them are proven
to have correlations with diseases. Indonesia consists of diverse ethnicity people and populations. It carries a unique genetic diversity
between one and another geographical positions. This paper aims to
extract Indonesians HLA allele data, mapping the data, and correlating
them with global diseases. From the study, it is found that global
diseases, like Crohnâs disease, rheumatoid arthritis, Gravesâ disease,
gelatin allergy, T1D, HIV, systemic lupus erythematosus, juvenile
chronic arthritis, and Mycobacterial disease (tuberculosis and leprosy)
suspected associated with the Indonesian HLA profiles
Time-Dependent Ionization in Radiatively Cooling Gas
We present new computations of the equilibrium and non-equilibrium cooling
efficiencies and ionization states for low-density radiatively cooling gas
containing cosmic abundances of the elements H, He, C, N, O, Ne, Mg, Si, S, and
Fe. We present results for gas temperatures between 1e4 and 1e8 K, assuming
dust-free and optically thin conditions, and no external radiation. For
non-equilibrium cooling we solve the coupled time-dependent ionization and
energy loss equations for a radiating gas cooling from an initially hot, >5e6K
equilibrium state, down to 1e4K. We present results for heavy element
compositions ranging from 1e-3 to 2 times the elemental abundances in the Sun.
We consider gas cooling at constant density (isochoric) and at constant
pressure (isobaric). We calculate the critical column densities and
temperatures at which radiatively cooling clouds make the dynamical transition
from isobaric to isochoric evolution. We construct ion ratio diagnostics for
the temperature and metallicity in radiatively cooling gas. We provide
numerical estimates for the maximal cloud column densities for which the gas
remains optically thin to the cooling radiation. We present our computational
results in convenient on-line figures and tables (see
http://wise-obs.tau.ac.il/~orlyg/cooling/).Comment: 20 pages, 12 figures. ApJS in press. Electronic data available at
http://wise-obs.tau.ac.il/~orlyg/cooling
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